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Genome-wide cyclin gene evolution in Arabidopsis and Brassica reveals polyploidization-driven duplication and flowering-time associations.

Cyclin genes are plant cell cycle regulators that play essential roles in growth, development, and reproduction. However, the evolutionary dynamics and genomic organization of cyclin genes across the Brassicaceae family remain poorly understood, particularly in the context of allotetraploid genome evolution. Here, we investigated the diversity, expansion mechanisms, and potential functional diversification of cyclin genes across ten Brassicaceae genomes, including four Arabidopsis and six Brassica species. A total of 1087 cyclin genes representing 23 cyclin types were identified. Comparative genomic analyses revealed that cyclin gene expansion was strongly influenced by polyploidization in Brassica species, with 1845 duplication events involving 1063 genes. Whole-genome duplication was the predominant mechanism driving expansion, while both inter- and intra-genomic duplications contributed to gene retention in tetraploid Brassica species, with the highest duplication frequency observed in Brassica juncea. Across genomes, 120 physical gene clusters were identified, including homogeneous and heterogeneous types. Ortholog analysis between progenitor and allotetraploid species identified 852 orthologous pairs involving 366 genes, indicating extensive conservation following allotetraploid formation. Phylogenetic analysis resolved cyclins into three major clades, while expression-based clustering in Brassica napus grouped genes into four major clusters, suggesting functional diversification. Integration of pan-genomic and flowering-time QTL analyses further identified two cyclin genes, Bna21cycA2 and Bna113cycD4, which contain amino acid polymorphisms and represent putative candidate variations potentially associated with flowering-time variation across multiple genomes. These findings provide new insights into the evolutionary expansion, retention, and potential functional divergence of cyclin genes in Brassicaceae and highlight candidate loci for future functional studies and crop improvement.

Evolution, Molecular

Genomic signatures of cold adaptation in a Himalayan drosophilid.

Drosophila nepalensis is a cold-adapted drosophilid endemic to the Himalayan region. Its ability to survive in harsh, cold conditions makes it a valuable Drosophila model for investigating how adaptation to thermal extremes may influence species persistence under future climate change. Here, we report the first de novo genome assembly of D. nepalensis, based on a hybrid sequencing strategy that combines Illumina short reads and Oxford Nanopore long reads. Illumina sequencing generated 49.88 million 150 bp paired-end reads (∼14.96 Gbp), while Nanopore sequencing produced 1.35 million long reads totaling ∼0.76 Gbp. The assembled genome spanned ∼178 Mb with an N50 of 83.6 kb and 98% BUSCO completeness, comparable to other well-annotated Drosophila genomes. Annotation identified 10,560 protein-coding genes, including transcription factor-rich and stress-related domains such as zinc fingers, WD40 repeats, and ankyrin motifs. Comparative orthology analysis across 6 Drosophila species identified 14,168 orthologous clusters, of which 9,173 were shared among all 6 species, indicating a conserved core genomic set across the sampled taxa. D. nepalensis showed 83 unique orthogroups and 50 singletons, suggesting some lineage-specific gene expansions associated with cold adaptation and endemicity, including families encoding caspase-family apoptotic regulators, chromatin remodeling proteins (HMGB/protamine-like), and SNARE-domain vesicle trafficking factors. Gene family evolution analysis revealed the highest expansions in the cold-tolerant Himalayan drosophilid, D. nepalensis, including significant expansions in serine protease, chaperone, and neurotransmitter transporter families, alongside dramatic contractions of core histone gene families, suggesting lineage-specific chromatin remodeling and ecological specialization.

Drosophila nepalensis

Insights into glandular trichome biology from analysis of organ-specific gene expression programmes in cannabis, hop and tomato.

Glandular trichomes (GTs) are epidermal outgrowths in which diverse specialised (secondary) metabolites are synthesised and stored. Cannabis (Cannabis sativa L.) and its close relative hop (Humulus lupulus L.) have pharmaceutical and industrial significance due to the presence of these metabolites in their GTs. We examined the conservation or divergence of the specific transcriptional programmes underlying GT biology. To achieve this, we generated transcriptome atlases of trichomes, flower, leaf, stem and root for cannabis, hop and tomato. We found that 12.9, 10.1 and 16.8% of cannabis, hop and tomato genes, respectively, were expressed organ/tissue specifically across all organs/tissues. Transcription factors (TFs) on average accounted for 7.5% of the organ-specific transcriptome and likely regulate organ-specific functions. We also conducted weighted gene co-expression network analysis and gene regulatory network (GRN) analysis to identify key regulators of GT function across the species and validated our predictions by DNA affinity purification sequencing for a subset of the cannabis and tomato GT TFs. The GRNs specific to cannabis or hop GTs were enriched for TFs and target genes associated with specialised metabolism, reflecting their species-specific nature. Conversely, the shared GRN components (identified via orthology analysis) were involved in highly conserved processes, such as flavonoid biosynthesis, solute transport and metabolite storage. Together, these GRNs and the associated transcriptome atlases are valuable resources to improve our knowledge of GT function and organ-specific genome regulation.

Solanum lycopersicum

Unraveling the genomic blueprint of the Indian black soldier fly: From genome assembly to evolutionary insights.

The black soldier fly (BSF) (Hermetia illucens) has been renowned for its sustainable bioconversion capabilities, resulting in smart protein production with wide applications in animal feed, bioenergy, and biofertilizer. However, the genetic mechanisms underlying efficient bioconversion and productivity remain poorly understood. To advance strain-specific applications and strengthen genetic resource availability, we present the whole genome sequencing (WGS) data for an Indian isolate of black soldier fly. The assembled genome was 1.46 Gb with a scaffold N50 of 172.7 Mb, and a GC content of 42.6%. Furthermore, 64.17% of genomic sequences were masked as repeated, and 14,317 protein-coding sequences were identified. Variant analysis against the reference genome identified 34.44 million variants (∼33.25 million SNPs and ∼ 1.18 million INDELs), with the majority (99.3%) classified as MODIFIER, 0.54% as LOW impact, 0.14% as MODERATE, and only 0.003% as HIGH impact. Comparative genomic analysis with other related species revealed expansions of gene families in BSF associated with Immune effector (Antimicrobial peptides (AMPs), Lysozymes, and Peptidoglycan Recognition Protein (PGRP) and Detoxification (cytochrome P450 enzymes). Notably, AMPs in the Indian isolate showed enhanced copy number variation in defensin (27) and PGRP (40) compared to reference BSF, suggesting potential regional adaptations to pathogen exposure. Collectively, this genomic data provides an improved resource for evolutionary studies, functional genomics, and targeted genetic improvement of BSF for sustainable bioconversion applications.

Comparative genomics

De novo assembly of transcriptomes of six Hua species (Semisulcospiridae, Cerithioidea, Gastropoda).

Species in Semisulcospiridae are important in freshwater ecology and have great research value, yet their genomic resources remain very limited. Here, we present de novo assembled transcriptomes from six species of Hua in Semisulcospiridae, including Hua textrix (Heude, 1888), H. yangi L.-N. Du, J.-X. Yang & Chen, 2023, H. wujiangensis L.-N. Du, J.-X. Yang & Chen, 2023, and three undescribed species. Assembly was performed using Trinity, resulting in average contig lengths ranging from 716.6 to 883.3 bp and transcript numbers ranging from 147,147 to 268,741. Benchmarking Universal Single-Copy Ortholog (BUSCO) analysis was used to assess the transcriptome completeness. The functional annotation of transcripts for each species had over 18,000 BLAST hits, 17,000 GO terms, 15,000 KEGG pathways, 8,000 Pfam accessions, and 140 COG functional categories. This study provides valuable transcriptomic resources for the six Hua species, which can be used for various research of Semisulcospiridae, including biodiversity, phylogeny, and comparative genomics.

Transcriptome

The first chromosome-level genome of the lappet moth Trabala vishnou (Lepidoptera: Lasiocampidae).

Trabala vishnou (Lefèbvre, 1827) (Lepidoptera: Lasiocampidae) is a destructive leaf-eating pest that causes severe damage to forest ecosystems, leading to substantial economic losses. Herein, we sequenced and assembled a high-quality chromosome-level genome of T. vishnou using a combination of Illumina reads, PacBio HiFi reads, and High throughput Chromosome Conformation Capture (Hi-C) technologies. The genome size is 561.86 Mb and spans 25 chromosomes, exhibiting a high level of contiguity (scaffold/contig N50 = 21.75 Mb/20.67 Mb). Benchmarking Universal Single-Copy Orthologs (BUSCO) analysis a 99.5% completeness score for this genome assembly. Repeat elements constitute 62.66% of the genome. A total of 1,630 non-coding RNAs and 12,895 protein-coding genes have been identified within the genome. The first chromosome-level genome of T. vishnou serves as a valuable reference for elucidating the evolution of functional traits in Lasiocampidae family and will facilitate the development of strategies for controlling defoliating pests.

Animals

A high-quality chromosome-level genome assembly and annotation of the giant freshwater prawn (Macrobrachium rosenbergii).

The giant freshwater prawn, Macrobrachium rosenbergii, is native to Southeast Asia and is used in aquacultural practices worldwide. It is considered advantageous because of its rapid growth, high nutritional value, and economic benefits. As one of the three major freshwater aquaculture shrimp sources in China, a high-quality genome resource is of great significance for promoting the germplasm improvement of varieties. This study presents a high-quality chromosome-level genome assembly of M. rosenbergii that was generated by combining PacBio, MGI, and Hi-C reads. The assembled genome was 2.96 Gb in size, with a contig N50 of 0.64 Mb and a scaffold N50 of 55.76 Mb, which was positioned on 59 pseudo-chromosomes. The Benchmarking Universal Single-Copy Orthologs (BUSCO) analysis for genome assembly reached 94.37%. In total, 27,111 protein-coding genes were identified, of which 25,470 were functionally annotated. These results provide a foundation for future research into adaptive evolution, genomics, and molecular breeding in M. rosenbergii.

Animals

A telomere-to-telomere reference genome assembly of the red silk cotton tree (Bombax ceiba).

Bombax ceiba, an important ornamental tree and potential fiber resource in the textile industry, is widely distributed in tropical and subtropical regions. In this study, we assembled a nearly gap-free telomere-to-telomere (T2T) genome of B. ceiba using Illumina, PacBio High-fidelity (HiFi), ONT ultra-long, and Hi-C sequencing technologies. The genome spanned approximately 807.89 Mb, with a scaffold N50 of 16.58 Mb, and 754.68 Mb (93.41%) of genomic sequences were anchored onto 48 pseudo-chromosomes. Benchmarking Universal Single-Copy Orthologs (BUSCO) analysis revealed a completeness of 99.40%, identifying 1,378 single-copy and 213 duplicated genes out of 1,614. The genome contained 67.72% (547.11 Mb) repeat regions, with 39,708 predicted protein-coding genes. Collectively, our study provides valuable genomic data for investigating the evolutionary history of the Malvaceae family.

Genome, Plant

Annotated genome of the Atlantic dog whelk, Nucella lapillus.

Nucella lapillus is an important player in rocky shore food chains and has been a focal organism of ecological and evolutionary studies for decades. Despite poor dispersal, they have a broad geographic range, which makes them an ideal species to examine isolation by distance and selection across environmental gradients. Here we present the fully annotated genome of N. lapillus generated with Oxford Nanopore Techonology sequencing at ∼37× coverage. The genome assembly is 2.32 Gbp and consists of 2,525 contigs, with an N50 length of 2 Mbp. Repeat annotation identified 2,491 families that cover 67.56% of the genome, which is similar to other gastropods. Despite its large size and high proportion of repeats, the genome is of high quality. Benchmarking Universal Single-Copy Ortholog (BUSCO) analysis revealed a score of 96.8%. Functional annotation of the genome produced 45,848 protein-coding genes with a 96.6% BUSCO score. Genomic resources for mollusks lag behind that of other phyla, perhaps because many of their innate characteristics complicate DNA extraction, sequencing, and assembly. This new N. lapillus genome will increase our genomic understanding of the second largest phylum (and the most diverse class within said phylum) and serve as a key resource to advance studies on the organismal biology and population genetics of this iconic species as well as the connection between genomic variation and community-level processes.

Animals

Chromosome-Scale Genome of Zoonotic Eyeworm Thelazia callipaeda from China.

Thelazia callipaeda is a vector-borne zoonotic eyeworm infecting companion animals, wildlife, and humans, but chromosome-scale genomic resources from Chinese clinical material remain limited. We generated a genome supported by Pacific Biosciences (PacBio) high-fidelity (HiFi) sequencing and high-throughput chromosome conformation capture (Hi-C) from 100 adult worms recovered from naturally infected dogs in Beijing and compared its chromosome-scale organization with Portuguese assembly GCA_965194785.1. The final assembly spans 119.53 megabases (Mb) and comprises 115 top-level sequences, including four pseudomolecules totaling 91.26 Mb (76.34%) and 111 unanchored sequences. Genome-mode Benchmarking Universal Single-Copy Orthologs (BUSCO) analysis recovered 98.5% complete chromadorean orthologues, and the representative 11,788-protein gene set recovered 92.6%. Sequence-level alignment resolved Chinese chromosomes 1-4 (chr1-chr4) to Portuguese chr1, chrX, chr3, and chr2, respectively, with retained alignments covering 95.9-99.2% of each Chinese pseudomolecule and estimated sequence identities of 99.75-99.91%. Strong chromosome-scale collinearity was accompanied by localized reverse-collinear regions, including 0.243 Mb and 0.115 Mb intervals on chr2-chrX and chr3-chr3. The anchored sequences contained 96.7% of predicted genes and were substantially more gene-dense than the unanchored sequences. These results establish a clinically sourced Chinese chromosome-scale reference and provide a validated framework for future individual-worm, population-genomic, structural-variation, and comparative genomic studies of this parasite.

Hi-C

KINAID: an orthology-based kinase-substrate prediction and analysis tool for phosphoproteomics.

SUMMARY: Proteome-wide datasets of phosphorylated peptides, either measured in a condition of interest or in response to perturbations, are increasingly becoming available for model organisms across the evolutionary spectrum. We introduce KINAID (KINase Activity and Inference Dashboard), an interactive and extensible tool written in Dash/Plotly, that predicts kinase-substrate interactions, uncovers and displays kinases whose substrates are enriched amongst phosphorylated peptides, interactively illustrates kinase-substrate interactions, and clusters phosphopeptides targeted by similar kinases. KINAID is the first tool of its kind that can analyze data from not only Homo sapiens but also 10 additional model organisms (including Mus musculus, Danio rerio, Drosophila melanogaster, Caenorhabditis elegans, and Saccharomyces cerevisiae). We demonstrate KINAID's utility by applying it to recently published S. cerevisiae phosphoproteomics data. AVAILABILITY AND IMPLEMENTATION: Webserver is available at https://kinaid.princeton.edu; open-source python library is available at https://github.com/Singh-Lab/kinaid; archive is available at https://doi.org/10.24433/CO.8460107.v1.

Proteomics

Genome-wide characterization of NOD-like receptor genes links NLR repertoire evolution to spleen immune responses after Aeromonas hydrophila challenge in the Chinese spiny frog (Quasipaa spinosa).

NOD-like receptors (NLRs) are cytosolic pattern-recognition receptors that detect pathogen-associated and damage-associated molecular patterns and mediate innate immune signaling in vertebrates. However, the genomic repertoire, evolutionary diversification, and infection-associated expression of NLR genes remain poorly defined in non-model amphibians. In this study, 66 NLR genes were identified from the Chinese spiny frog (Quasipaa spinosa) genome and designated as QsNLR1-QsNLR66. These genes were unevenly distributed across chromosomes and were classified into three phylogenetic groups, with most members exhibiting conserved motif architectures. Gene duplication analysis indicated that dispersed duplication was the main contributor to QsNLR expansion. Synteny analysis detected five conserved orthologous gene pairs between Q. spinosa and Pelophylax nigromaculatus, suggesting partial conservation of NLR genomic organization between the two amphibians. Ka/Ks analysis showed that several duplicated gene pairs, including NLRC3-like/QsNLR36 and NLRC3-like/QsNLR50, exhibited Ka/Ks ratios greater than one, suggesting potential sequence divergence after duplication. Spleen RNA sequencing (RNA-seq) after Aeromonas hydrophila challenge revealed enrichment of immune-related Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Weighted gene co-expression network analysis linked several QsNLRs to infection-associated modules, among which QsNLR57 was co-expressed with CYBB, ADAM17, SPI1, and HK2. RT-qPCR using time-matched phosphate-buffered saline (PBS) controls showed distinct temporal patterns, with stronger induction of QsNLR29, QsNLR57, and QsNLR66 and weaker or delayed responses of QsNLR50 and QsNLR56. These results characterize the NLR repertoire of Q. spinosa and identify infection-associated QsNLR candidates for future studies of antibacterial immunity in amphibians.

Animals

Fine mapping of the dominant female sterility gene and novel model of hybrid seed production in cabbage (Brassica oleracea L. var. capitata).

Hybrid breeding based on male sterility requires the removal of male parents, which is time- and labor-intensive; however, the use of female sterile male parent can solve this problem. In the offspring of distant hybridization between Brassica oleracea and Brassica napus, we obtained a mutant, 5GH12-279, which not only fails to generate gynoecium (thereby causing female sterility) but also has serrated leaves that could be used as a phenotypic marker in seedling screening. Genetic analysis revealed that this trait was controlled by a single dominant gene. Further analysis revealed that Bo2g005230, an orthologous gene of LATE MERISTEM IDENTITY1 (LMI1) in Arabidopsis, was predicted as the candidate gene and was renamed BoLMI1c. Sequence analysis revealed that homoeologous exchange (HE) occurred within the BoLMI1c gene body of 5GH12-279, which resulted in the generation of a novel fusion transcript. Two pairs of primers, N5230-1F/1R and N5230-2F/2R, were designed and successfully used for the identification of different genotypes of BoLMI1c. Transcriptome analysis revealed that BoLMI1c orchestrates the expression of several related biological processes and transcription factors. Furthermore, we found that self-pollination with mason bees produced no seeds in 5GH12-279, whereas the near-isogenic line 5GH12-170 produced seeds that were normal. Therefore, a new labor-saving hybrid seed production system with no need to remove the male parents, which is especially important for mechanized harvest in the future, has been proposed. Our study provides a valuable source of dominant female sterility and suggests the potential utilization of the female sterile line in hybrid breeding for mechanized harvest.

Plant Infertility

Genomic profiling of digestion related enzymes in Anopheles aquasalis a major coastal neotropical malaria vector.

Digestive genes are fundamental for the development and survival of mosquitoes and can serve as a target for the development of strategies for mosquito control or vector-borne disease prevention. Genes related to digestion were identified in the genome of the neotropical malaria vector Anopheles aquasalis by similarity. We used reciprocal BLAST with annotated digestion proteins for Anopheles gambiae. Orthology and evolutionary analyses were performed using MEGA with a bootstrapped phylogenetic tree constructed by the neighbor-joining method, and copy number variation was measured by the standard deviation of the average copy number in each gene family. We identified 241 genes related to digestion in An. aquasalis: 56 genes related to carbohydrate digestion, 51 genes for lipid digestion, and 134 genes for protein digestion. Phylogenetic relationships with other anophelines show that An. aquasalis genes are closely related to those of neotropical mosquitoes Anopheles darlingi and Anopheles albimanus. Orthologous gene clusters are conserved in important families of all four species. Some of these conserved genes are of interest for studies on controlling mosquito vectors, such as larvicidal toxin receptor genes, alpha-amylase, alpha-glucosidase, and maltase; important target genes for transmission-blocking vaccines, such as aminopeptidase N1 and carboxypeptidase B; and the major intestinal serine proteases, such as trypsins and chymotrypsins, which can positively or negatively affect Plasmodium development in the midgut. These data provide a better understanding of digestion-related genes in American anopheline mosquitoes and may support further fundamental and applied studies aimed at malaria control.

Animals

Heterologous expression of DobHLH25 from Dendrobium officinale enhances drought tolerance in Arabidopsis.

Drought stress severely constrains the growth, yield, and accumulation of bioactive compounds in Dendrobium officinale (D. officinale), a valuable medicinal orchid, and this challenge is exacerbated under simulated wild cultivation where plants are inevitably exposed to recurring water deficits. Basic helix-loop-helix (bHLH) transcription factors are well-established regulators of plant abiotic stress responses. However, the molecular mechanisms by which bHLH transcription factors respond to drought stress in this species remain largely unknown. In this study, a bHLH transcription factor gene, DobHLH25, was cloned from D. officinale. Phylogenetic analysis revealed that DobHLH25 shares the highest sequence identity with its ortholog in Dendrobium nobile. Additionally, subcellular localization analysis indicated that DobHLH25 is targeted to the nucleus and possesses a functional transcriptional activation domain. Expression pattern analysis showed that DobHLH25 is most abundantly expressed in old leaves, and its expression in roots, stems, and leaves is induced by polyethylene glycol treatments. Heterologous expression of DobHLH25 in Arabidopsis thaliana resulted in higher seed germination rates and longer root lengths under mannitol-induced osmotic stress compared to wild-type plants. Under drought stress, DobHLH25 heterologous expression lines exhibited higher survival rates, reduced leaf water loss, lower malondialdehyde accumulation, and increased proline content. Moreover, the activities of antioxidant enzymes such as superoxide dismutase and peroxidase were significantly enhanced, and the expression levels of multiple drought-responsive genes were markedly upregulated. Collectively, these findings suggest a correlation between DobHLH25 expression and plant drought tolerance, as evidenced by reduced oxidative damage, increased osmolyte accumulation, enhanced antioxidant enzyme activities, and upregulation of drought-responsive genes. Together, these results suggest that DobHLH25 plays a positive role in drought tolerance, and provides a basis for future dissection of its regulatory network in D. officinale.

Drought Resistance

Genomic analysis of regulatory mechanisms governing EPS66A biosynthesis in Streptomyces changanensis HL-66.

Streptomyces changanensis HL-66 produces the α-(1,4)/(1,6)-glucan exopolysaccharide EPS66A, a potent plant immune elicitor with promising applications in plant protection. However, its low native fermentation yield limits large-scale application. To investigate the biosynthetic potential and regulatory mechanisms underlying EPS66A production, the whole genome of HL-66 was sequenced and analyzed. The HL-66 genome is 6.82 Mb in size, with a GC content of 74%, and encodes 6081 predicted functional genes. Among these, 1390 genes were annotated to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, 4187 were assigned to Gene Ontology (GO) terms, and 143 were classified into Clusters of Orthologous Groups (COG) categories. antiSMASH analysis identified 22 secondary metabolite biosynthetic gene clusters, including multiple polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) clusters. Functional analyses revealed that the glycosyltransferase gene (GTy) and the global regulatory gene (bldD) are involved in EPS66A biosynthesis. bldD is involved in morphological development and EPS66A production, whereas GTy specifically regulates EPS66A production without affecting growth or development. In both in vivo and potted-plant experiments, EPS66A (200 μg/mL) significantly reduced the severity of tobacco mosaic virus, apple anthracnose leaf spot, walnut bacterial leaf spot, and jujube anthracnose, achieving control efficacies of 90.21%, 87.95%, 77.41%, and 68.55%, respectively, and outperforming a commercial chitosan oligosaccharide control. These findings provide new insights into the genetic architecture and regulatory mechanisms of EPS66A biosynthesis and support its development as a polysaccharide-based green pesticide.

Streptomyces

Whole-genome sequencing and analysis of the endophytic fungus Alternaria alternata Y-2 from Leymus chinensis.

To explore the genetic basis and functional potential of beneficial symbiosis between the endophytic fungus Alternaria alternata Y-2 and its host Leymus chinensis, we performed Illumina-based draft whole-genome sequencing and systematic bioinformatic analysis. Although this assembly does not reach telomere-to-telomere completeness, it provides high-quality gene-level information for gene prediction, functional annotation, carbohydrate-active enzyme (CAZyme) identification, and secondary metabolite biosynthetic gene cluster analysis. The final genome size of A. alternata Y-2 was 34,383,676 bp with a GC content of 51.0%, containing 12,724 predicted protein-coding genes, 90 tRNAs, and 12 rRNAs. BUSCO assessment showed 98.9% completeness, supporting the high quality of this draft genome. A total of 12,627 genes were successfully annotated in the NCBI NR database, and 17,183 genes were functionally categorized using GO terms. In total, 448 CAZyme genes and 21 secondary metabolite biosynthetic gene clusters were identified, which are potentially involved in lignocellulose degradation, cellular redox homeostasis and biosynthesis of bioactive metabolites. Based on ITS sequence alignment, NR annotation, and phylogenetic analysis of single-copy orthologous genes, the strain was confidently identified as A. alternata. This study firstly reports the draft genome of an endophytic A. alternata strain derived from L. chinensis and provides valuable genetic resources for exploring the endophytic lifestyle, stress tolerance, and bioactive metabolite potential of this fungus.

Alternaria

Chitosan-dsRNA improves tissue stability and delivery for RNAi-mediated Varroa destructor control.

BACKGROUND: Varroa destructor is an ectoparasitic mite and a major threat to honey-bee colony health worldwide. RNA interference (RNAi) offers a potentially species-specific approach for mite control, but practical application is limited by double-stranded RNA (dsRNA) degradation and inefficient delivery to mites. This study evaluated coatomer protein I (COPI) complex subunits as RNAi targets and tested whether chitosan-based dsRNA formulation could improve dsRNA stability, tissue uptake, and delivery from honey-bees to mites. RESULTS: Direct microinjection of dsRNAs targeting COPB, COPD, and COPE significantly reduced target-gene expression and mite survival compared with the double-stranded green fluorescent protein (dsGFP) control, with 72-h survival rates of 8.0%, 12.7%, and 5.3%, respectively, compared with 40.7% in the control group (all log-rank P&#x2009;<&#x2009;0.0001). Chitosan-conjugated dsRNA remained detectable for longer periods than naked dsRNA in honey-bee tissue fluids, and CNP-Cy3-dsGFP was detected in the honey-bee midgut and fat body. A qualitative fluorescence observation in V. destructor was consistent with host-to-mite dsRNA transfer. Ingestion of COP-targeted chitosan-dsRNAs reduced mite survival, whereas honey-bee survival and expression of honey-bee COP orthologs were not affected. In silico analysis detected no contiguous &#x2265;19-nt matches between Varroa COP dsRNAs and the honey-bee transcriptome or genome. CONCLUSION: COPI subunits are promising RNAi targets in V. destructor, and chitosan formulation may improve dsRNA persistence and uptake while supporting honey-bee-mediated delivery to mites. These laboratory findings support further evaluation of chitosan-formulated dsRNA as a potentially species-selective strategy for Varroa management, while broader safety assessment and field validation remain necessary. &#xa9; 2026 Society of Chemical Industry.

COPI complex